A look into the tracking systems of the Detroit LionsFebruary, 24, 2015By Michael Rothstein | ESPN.com

ALLEN PARK, Mich. -- The staffer walked around the locker room daily after practices and walkthroughs. He’d go to each player and quickly click on a sensor.

Sometimes, he’d grab the heart monitors from the shirts of Detroit Lions players.

Every scan had a purpose, information gathering used to try and help the Lions win games Sundays as they searched for some sort of edge over the rest of the teams in the league. Every team in the NFL -- and every player in the league -- has radio frequency technology in their shoulder pads and around stadiums on game day to measure various movements.

The Lions are believed to be the only team in the league to use the radio-based technology daily. The team, using a system installed by Zebra Technologies, had sensors sewn into practice jerseys to be able to track information even during non-padded practices as part of their analytic analysis. This goes along with a heart rate monitor the Lions players wear on Zephyr undershirts specifically equipped with a snap-on sensors to measure other performance levels.

“At first it’s weird, but once you’re out there at practice, your mind is on everything else,” receiver Ryan Broyles said last season. “When you’re out there and you’ve got pads on and all that stuff, it’s not really that big of a deal. But it tracks a lot of stuff.

“It tracks how fast you go, how much force you put in the ground, the distance you cover and the heart rate monitor shows how high your heart rate is or your intensity is.”

The Lions deem this information valuable as supplemental data. The technology helped with measuring a player’s true recovery from injury. In at least one instance last season, a player thought he was ready to return but the data collected by the franchise and then measured to the recovering player had him sit out one more week.

The Zephyr tracker and the Zebra technology have combined to give Detroit a still-emerging picture of how deep analytics could go. Team president Tom Lewand told ESPN.com last season the Lions had their system specifically developed and installed in their Allen Park, Michigan practice facility. This included sensors -- essentially looking like ordinary poles -- around the outskirts of the practice field to help measure various levels of output and distance.

“It gives you a good sense of how much work is being done by the players, how much physical exertion and some other things,” Lewand said. “Without getting too much into the detail of it, it certainly can measure a lot of the physical activity and physical load not just from a distance and miles run, but actually how much exertion there is, what heart rates are, those kinds of things.”

Lewand often declined to give specifics of the system -- one he said was the only one of its kind in the NFL -- during an interview with ESPN.com. Players throughout the season said the coaching staff used the information to taper practices based off the data.

The franchise installed the system on a minimal basis in 2013 and used it extensively for the first time last season. The Lions are tweaking it constantly to find new uses for it. One use came in using the technology to help give information about free agents the team worked out weekly.

Lewand said Lions coach Jim Caldwell has been “a huge part of developing it and customizing” the technology based on what his coaching staff wants to see since being hired in January, 2014. As for exactly what that data is -- Lewand and the Lions declined to delve into specifics. In addition to the system, the Lions had senior coaching assistant Gunther Cunningham dive heavily into analytics and Pro Football Focus last season -- .

As far as games go -- and this is something he said could be implemented league-wide eventually -- the system they have can overlay routes run onto game film to measure exact distances covered. It can tell how close a receiver was running to a defensive back and how fast they are in comparison to each other. It can tell how fast a defensive lineman moves off the ball.

All of this information could end up working their way into coaching information and even television broadcasts. This has already shown up when broadcasts show how far a player ran when breaking down certain plays.

That, though, is just the beginning of what can be done.

“I think you’ll see those statistics start coming out as part of the growth of that particular industry,” Lewand said. “As far as the possibilities internally, there are a lot. We’re using some now.

“We’re exploring some other ones actively, and I’m sure there are other ones that our imaginations haven’t gotten to yet.”